Effects of Prism Adaptation on Left and Right Spatial Neglect in Patients with Subacute Stroke: A Multi-Centred Randomized Controlled Trial

OBJECTIVE: To investigate the effects of prism adaptation (PA), using a left or right visual shift prism, in terms of improving left spatial neglect (LSN) or right spatial neglect (RSN) in patients after subacute stroke. METHODS: This was a randomized controlled trial with 3 inpatient sites. Forty-eight participants (PA: 25; control: 23) completed the interventions, they were further stratified into LSN and RSN according to the neglect sides. Participants in the 2 intervention arms - PA and control, received the same pointing tasks, with the only difference being participants in the PA group wore a pair of prisms inducing a 5.7° optical shift to the right or left, while participants in the control group wore plain (sham) glasses, in the exposure stage. The training lasted for 20 to 30 minutes per session, for 10 sessions across 2 weeks. Main measures were Behavioural Inattention Test, Catherine Bergego Scale, and Modified Barthel Index were rated at 4 timepoints. RESULTS: Both the PA and control groups improved over time. The gain scores for all outcomes in the PA group were significantly higher than that in the control group. Subgroup analyses showed that the gain scores in the PA-LSN and PA-RSN groups were significantly higher than in the sham-LSN and sham-RSN groups, respectively. CONCLUSION: PA is effective for poststroke spatial neglect recovery and performs better than a sham adaptation in terms of the amelioration of symptoms of neglect and daily functioning improvement in patients with LSN and RSN, but more benefits can be seen for LSN. CLINICAL TRIAL REGISTRY: (Ref. no.: ChiCTR2100052573).